GEOMORPHIC ASPECTS OF POST-FIRE FLOODING AFTER THE SCHULTZ FIRE, SAN FRANCISCO PEAKS, COCONINO NATIONAL FOREST, ARIZONA

The Schultz Fire burned approximately 15,051 acres on the eastern slopes of the San Francisco Peaks in Coconino National Forest between June 20^th and June 30, 2010. The wildfire was contained adjacent to private lands and several developments. A Forest Service Burned Area Emergency Response Team (BAER) completed an assessment of the burn area by July 10, 2010 reporting the high potential for post-fire flooding, sedimentation and possible debris flows due to the severity of the fire and the geomorphic setting. 39% of the burn area (>5,000 acres) was high-severity burn largely concentrated on steep mountain terrain with slopes >30%. The steep slopes of the San Francisco Peaks have a series of ephemeral mountain drainages that descend to a bajada below. This geomorphic setting paired with high-intensity monsoon precipitation over the burn area resulted in multiple flood events with sheet-flooding extending into the communities below. A series of four parallel transects across the burn area perpendicular to the flow-path of the affected drainages have been established to evaluate the magnitude of the flood flows and to monitor surface processes across an elevation gradient. Here we discuss the geomorphic attributes that contribute to the post-fire flooding and dictate the success of efforts at flood mitigation.